Railgun shafts are engineered from ultra tough oil-quenched carbon spring steel. Highly durable 6mm threads. Size Chart: 110cm - 70cm speargun120cm - 80cm speargun130cm - 90cm speargun140cm - 100cm speargun150cm - 110cm speargun160cm - 120cm speargun170cm - 130cm speargun180cm - 140cm speargun